Parameters:

IN/OUT: Pointer to the instance of H5AC_cache_config_t in which the current metadata cache configuration is to be reported. The fields of this structure are discussed below:

General configuration section:

intversion

IN: Integer field indicating the the version of the H5AC_cache_config_t in use. This field should be set to H5AC__CURR_CACHE_CONFIG_VERSION (defined in H5ACpublic.h).

hbool_trpt_fcn_enabled

OUT: Boolean flag indicating whether the adaptive cache resize report function is enabled. This field should almost always be set to FALSE. Since resize algorithm activity is reported via stdout, it MUST be set to FALSE on Windows machines.

The report function is not supported code, and can be expected to change between versions of the library. Use it at your own risk.

hbool_topen_trace_file

OUT: Boolean field indicating whether the trace_file_name field should be used to open a trace file for the cache. This field will always be set to FALSE in this context.

hbool_tclose_trace_file

OUT: Boolean field indicating whether the current trace file (if any) should be closed. This field will always be set to FALSE in this context.

char *trace_file_name

OUT: Full path name of the trace file to be opened if the open_trace_file field is TRUE. This field will always be set to the empty string in this context.

OUT: The factor by which the current maximum cache size is multiplied to obtain an initial new maximum cache size if a size increase is triggered in the hit rate threshold cache size increase algorithm.

hbool_tapply_max_increment

OUT: Boolean flag indicating whether an upper limit will be applied to the size of cache size increases.

size_tmax_increment

OUT: The maximum number of bytes by which the maximum cache size can be increased in a single step -- if applicable.

enum H5C_cache_flash_incr_modeflash_incr_mode

OUT: Enumerated value indicating the operational mode of the flash cache size increase code. At present, only the following values are legal:

OUT: The factor by which the current maximum cache size is multiplied to obtain the minimum size entry / entry size increase which may trigger a flash cache size increase.

doubleflash_multiple

OUT: The factor by which the size of the triggering entry / entry size increase is multiplied to obtain the initial cache size increment. This increment may be reduced to reflect existing free space in the cache and the max_size field above.

Decrement configuration section:

enum H5C_cache_decr_modedecr_mode

OUT: Enumerated value indicating the operational mode of the automatic cache size decrease code. At present, the following values are legal:

OUT: Upper hit rate threshold. This value is only used if the decr_mode is either H5C_decr__threshold or H5C_decr__age_out_with_threshold.

doubledecrement

OUT: Factor by which the current max cache size is multiplied to obtain an initial value for the new cache size when cache size reduction is triggered in the hit rate threshold cache size reduction algorithm.

hbool_tapply_max_decrement

OUT: Boolean flag indicating whether an upper limit should be applied to the size of cache size decreases.

size_tmax_decrement

OUT: The maximum number of bytes by which cache size can be decreased if any single step, if applicable.

intepochs_before_eviction

OUT: The minimum number of epochs that an entry must reside unaccessed in cache before being evicted under either of the ageout cache size reduction algorithms.

hbool_tapply_empty_reserve

OUT: Boolean flag indicating whether an empty reserve should be maintained under either of the ageout cache size reduction algorithms.

doubleempty_reserve

OUT: Empty reserve for use with the ageout cache size reduction algorithms, if applicable.

Parallel configuration section:

intdirty_bytes_threshold

OUT: Threshold number of bytes of dirty metadata generation for triggering synchronizations of the metadata caches serving the target file in the parallel case.

Synchronization occurs whenever the number of bytes of dirty metadata created since the last synchronization exceeds this limit.

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H5F_GET_MDC_CONFIG loads the current metadata cache configuration into the instance of H5AC_cache_config_t pointed to by the config_ptr parameter.

Note that the version field of *config_ptr must be initialized --this allows the library to support old versions of the H5AC_cache_config_t structure.

See the overview of the metadata cache in the special topics section of the user manual for details on metadata cache configuration. If you haven't read and understood that documentation, the results of this call will not make much sense.